To provide a pressure detector which, when a case is mounted to a predetermined mounting surface, can inhibit a liquid from collecting in a liquid phase section, and let the liquid and a gas that have flowed into the liquid phase section smoothly flow out through an outflow port.SOLUTION: The pressure detector comprises: a case C； and a diaphragm member M which partitions a liquid phase section S1 into which a liquid can be filled and a gas phase section S2 into which a gas can be filled, and which is displaceable according to the pressure of the liquid filled in the liquid phase section S1； the pressure detector detecting the pressure of the gas phase section S2 to detect the pressure of the liquid. The pressure detector further includes an inflow port C1 and an outflow port C2, and an outflow opening Ca2 is formed at a position including an uppermost portion of the liquid phase section S1 in a vertical direction Z when the case C is mounted to the predetermined mounting surface U, the outflow port C2 being formed in such a way as to incline upwardly from the outflow opening Ca2.SELECTED DRAWING: Figure 10【課題】ケースが所定の取付面に取り付けられた状態において液相部内に気体が溜まってしまうのを抑制できるとともに、液相部に流入した液体及び気体を流出ポートを介して円滑に流出させることができる圧力検出器を提供する。【解決手段】ケースＣと、液体を充填し得る液相部Ｓ１と、気体を充填し得る気相部Ｓ２とを区画するとともに、液相部Ｓ１に充填された液体の圧力に応じて変位可能な膜部材Ｍとを具備し、気相部Ｓ２の圧力を検出することにより液体の圧力を検出する圧力検出器において、流入ポートＣ１及び流出ポートＣ２を有し、流出口Ｃａ２は、ケースＣが所定の取付面Ｕに取り付けられた状態において鉛直方向Ｚに対する液相部Ｓ１の最上部を含む位置に形成されるとともに、流出ポートＣ２が流出口Ｃａ２から上方に向かって傾斜しつつ形成されたものである。【選択図】図１０
